Uploaded July 2025 | Updated September 2026, 2 weeks ago
California has been known as the largest state Democratic stronghold in the nation for decades, with no Republican candidate winning the state’s coveted electoral college votes since 1988. In the 2024 presidential election, however, just under 59% of Californians voted for the Democratic nominee, Vice President Kamala Harris, resulting in the state’s smallest Democratic vote share in a presidential general election since 2004. A similar story of decline and a corresponding increase in the vote share of Republicans was seen in many jurisdictions across the country, prompting much speculation as to why this occurred and whether it will endure in future elections, especially among young voters and voters of color.
CID recently released a research brief focused on California that provides a better understanding of the increased Republican vote share in the state’s 2024 general election by placing the results within a greater historical context. We examine the changing official party registration of California’s registered voters between the presidential elections of 2008 and 2024, while also breaking out the degree of change by race, ethnicity, age and their intersection.
Mindy Romero, Ph.D., CID Director (moderator)
Mike Madrid, Political Consultant
Paul Mitchell, Vice President, Political Data, Inc.
Eric McGhee, Ph.D., Policy Director and Senior Fellow, Public Policy Institute of California
This research was generously supported through funding from the Evelyn and Walter Hass, Jr. Fund.
California has been known as the largest state Democratic stronghold in the nation for decades, with no Republican candidate winning the state’s coveted electoral college votes since 1988. In the 2024 presidential election, however, just under 59% of Californians voted for the Democratic nominee, Vice President Kamala Harris, resulting in the state’s smallest Democratic vote share in a presidential general election since 2004. A similar story of decline and a corresponding increase in the vote share of Republicans was seen in many jurisdictions across the country, prompting much speculation as to why this occurred and whether it will endure in future elections, especially among young voters and voters of color.
CID recently released a research brief focused on California that provides a better understanding of the increased Republican vote share in the state’s 2024 general election by placing the results within a greater historical context. We examine the changing official party registration of California’s registered voters between the presidential elections of 2008 and 2024, while also breaking out the degree of change by race, ethnicity, age and their intersection.
Mindy Romero, Ph.D., CID Director (moderator)
Mike Madrid, Political Consultant
Paul Mitchell, Vice President, Political Data, Inc.
Eric McGhee, Ph.D., Policy Director and Senior Fellow, Public Policy Institute of California
This research was generously supported through funding from the Evelyn and Walter Hass, Jr. Fund.
